设原来的速度为v
则 v=5/6 /(1-5/6) =5
甲、乙两地的距离=
(3+1/12) /(1/(v-1)-1/v)
=(3+1/12)/ (1/4-1/5)
=(37/12) /(1/20)
=20*37/12
=5*37/3
=185/3
设原来的速度为v
则 v=5/6 /(1-5/6) =5
甲、乙两地的距离=
(3+1/12) /(1/(v-1)-1/v)
=(3+1/12)/ (1/4-1/5)
=(37/12) /(1/20)
=20*37/12
=5*37/3
=185/3